Hydration of nitriles in the presence of water has been accomplished by a number of copper catalysts. For example, Greene in U.S. 3,381,034 reacted various nitriles with water in the presence of soluble copper ions. The present invention is distinguished over this art because the catalysts of the invention contain catalytic copper metal. In contrast, Greene used massive copper metal to make her catalysts and stated that this metal was not catalytic.
Watanabe in Bull. Chem. Soc. Japan, 32, 1280 (1959); 37, 1325 (1964); and 39, 8 (1966) shows the use of reduced copper chloride, a catalyst useful in the present invention. His catalysts were prepared by contacting copper chloride with zinc and were employed only to convert benzonitrile to benzamide. In contrast, the present invention converts aliphatic nitriles to the corresponding amide. Watanabe in Bull. Chem. Soc. Japan, 37, in the left column of p. 1325 makes the broad statement that "[the] reaction of aliphatic nitriles is somewhat complicated and is different from that of aromatic ones: the yield of the amides is comparatively lower than that from aromatic nitriles, and the hydration reaction is accompanied by side reactions forming some acidic compounds." Although this general statement is apparently based on work done with nickel catalysts, it would be expected that similar results would be obtained with copper compounds. Contrary to this expected result, it has been found that for catalysts which contain catalytic copper, the reaction forms litle or no by-products.